


Ten to One

by Amelia_Clark



Series: 30 Day Cheesy Trope Challenge [16]
Category: Supernatural
Genre: Confused Dean, Cunnilingus, Gender or Sex Swap, Magical Artifacts, Non-Binary Castiel, Other, Vaginal Sex
Language: English
Status: Completed
Published: 2014-11-25
Updated: 2014-11-26
Packaged: 2018-02-27 00:26:02
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 2,794
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2672027
Author URL: https://archiveofourown.org/users/Amelia_Clark/pseuds/Amelia_Clark
Summary: <blockquote class="userstuff">
              <p>The woman in Dean's bed stirs, turns to him with a yawn, and the eyes she opens are a shade of blue he'd recognize anywhere. "Good morning, Dean," she says in a rich contralto, and her eyes widen; her hand flies to her throat, probes the absence of an Adam's apple. She sits up, frowning in that unmistakable way, and slides her hand down to clutch a bare breast.</p><p>"Dean," says Cas—because that's who it is, even though that's impossible—"something happened to me overnight."</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> **#28: Sex-swapped AU  
> **   
> 

Dean wakes up with a woman in his bed.

Which is not, in itself, alarming—except he'd gone to sleep with Cas next to him, mussed and half-naked and pleasantly spent; waking up alone would've been surprising enough, but he's got no fuckin' idea how Cas could've slipped out and this woman crept in without his waking up for at least part of it.

She stirs, turns to him with a yawn, and the eyes she opens are a shade of blue he'd recognize anywhere. "Good morning, Dean," she says in a rich contralto, and her eyes widen; her hand flies to her throat, probes the absence of an Adam's apple. She sits up, frowning in that unmistakable way, and slides her hand down to clutch a bare breast.

"Dean," says Cas—because that's who it is, even though that's impossible—"something happened to me overnight."

"Yeah, I got that," Dean says. He props himself up on an elbow, which has the unfortunate effect of putting...Cas's...boobs right in his line of sight. Okay, it's not unfortunate at all, as they're pretty damn nice to look at; still, it feels impolite. _His eyes are up there,_ he chides himself, and he drags his gaze back to Cas's face. While his jaw is narrower, and there's an unsettling lack of stubble, the eyes and mouth are the same, and his dark hair's still short, giving him the pixie-ish look that Dean doesn't usually go for.

Today, though, is obviously unusual.

Cas, of course, is unfazed by his nudity, squeezing and poking his newly feminine flesh. He throws the covers off to investigate further; he's wearing the boxers he fell asleep in, tight over rounded hips and thighs. When Cas slips a hand between his legs, Dean reaches his breaking point, and he springs out of bed like a jack-in-the-box.

"Hey, we should—let's go wake up Sam, I think this is all hands on deck for research, don't you?" He heads for his dresser swiftly, turning his back on his topless boyfriend. Girlfriend? Cas.

"Yes, you're right. This must be a spell of some kind," Cas says. His voice is an octave higher than usual, but that's not saying much; it's low, rumbly, and Dean has a weird flashback to being a kid, ogling Jessica Rabbit's impossible curves while Kathleen Turner purred "I'm not bad, I'm just drawn that way."

"A spell! Yeah! Sam can help, hit the books, figure this shit out." Dean tugs on his jeans, touching his cock as little as possible while he zips up his fly. "You'll need a shirt," he says as he grabs one for himself. There's one at the back of the drawer that shrunk in the wash, maybe that'll fit Cas's new body.

But when he risks a peek, Cas is already dressed in the same button-down and slacks he had on last night, and they're not a bad fit. Apparently he didn't lose any height, and he was pretty lean before; so while the pants cling to his ass and he has to roll up his sleeves a little, he looks good.

So good, in fact, that it doesn't help the situation in Dean's pants one bit, and it's a heroic effort not to just walk over there and take those clothes back off.

*******

Sam is understandably nonplussed, and his gaze moves down Cas's curves a little too slowly for Dean's taste. "It's gotta be a spell, right? Fuckin' witches?" says Dean, stepping between them.

"That's one possibility," Sam says, and he gets that excited I'm-on-the-case look he gets, the one that heralds a long, woodcut-heavy day of research. "What were you doing before it happened?"

"Performing fellatio on Dean," says Cas.

"Sleeping," Dean says loudly into the awkward pause. "You were, uh, you were definitely a dude when you fell asleep."

"Well, it doesn't seem likely that either of those—activities would cause the transformation on their own. I meant more, what were you up to yesterday? Weren't you in one of the artifact rooms?"

Yeah, because they'd gone in there to make out under the guise of being helpful. "I don't think we touched anything," Dean replies, but oh, wait. "No, we knocked over a box, and this stick thing fell out. We put it back, though, right where we found it."

"Stick thing," Sam says thoughtfully. "Can you show me?"

*******

It takes some embarrassing moments of re-creation ("No, Dean, you spun us around and pushed me up against _that_ shelf"), but they find the box and take it back to the library. The object isn't a stick so much as a short staff, with two carved snakes winding around it and wings fanning out from the top. "Oh, that explains it," says Sam. "It's a caduceus."

"A what? I don't get it," says Dean, glowering at the thing like it's gonna leap out and attack him.

"Caduceus," Sam repeats. "It gets used as a medical symbol a lot, but that's actually confusing it with the rod of Asclepius, which only has one snake. This is the rod of Hermes, but even before that, it belonged to Tiresias."

"Tiresias? The blind guy from the Odyssey?"

"Hey, ten points to Gryffindor!" says Sam, clapping him on the shoulder. "Yeah, same dude. And he gave Oedipus the bad news about his mom, too. But before any of that, the lore says he saw two snakes having sex, and he hit them with his staff—Hera got mad and turned him into a woman. So I guess that's what happened to Cas, he must've touched it accidentally when you picked up the box."

He's shining with triumph, but Dean doesn't feel it. "Did he change back?"

"He did. Seven years later."

*******

For once, Dean doesn't mind the hours stuck in the library, poring over old-ass books to find some way to fix things without having to wait for the better part of a decade. Cas is right there with them, but he doesn't seem to feel the urgency that Dean does—eons as a genderless wavelength have left him pretty indifferent to the exact nature of his physical form.

Dean's having some trouble dealing. He's just barely accepted that he's in love with and having sex with a man, still working on understanding that part of him, that it's been there all along and is nothing to be ashamed of—it feels like cheating to have Cas turn into a chick. He's plenty hot, Dean can totally picture them together (has been picturing it all day in a Technicolor blur of mental images), but—how can he still be bi if he's dating a girl? Was all that soul-searching, that bravery he summoned up to kiss Cas for the first time, for nothing?

He's still brooding when they finally call it a night; they've got a few leads for shortcuts, but nothing definite yet. Cas follows him into their room as usual, strips back down to boxers and climbs into bed. Dean hesitates after taking off his shoes, can't help but stare at Cas's boobs, think about what's under the unflattering underwear.

"What's wrong?" asks Cas.

"Can't you sleep in a shirt?" Dean manages to say. "I can't—I don't think you know how distracting you're being right now."

"I have an idea," says Cas indignantly. "I'm attracted to women as well, just like you. I know you're aroused looking at me."

"Then why won't you cover up?"

Cas rolls his eyes. "I'm trying to seduce you, Dean. I want to have sex while I'm like this."

Dean can't speak, and Cas continues calmly, "I came across an interesting tidbit while reading about Tiresias's experiences. It seems he was called to settle an argument between Zeus and Hera, about whether men or women felt more sexual pleasure. And he told them, 'of ten parts a man enjoys one only.'" Cas grins. "I'd like to test that theory."


	2. Chapter 2

**Notes for the Chapter:**

> So, yeah, I realized this isn't het sex at all. Dean's a cis male, but Cas is non-binary--or rather, his gender expression surpasseth human understanding. I kept up masculine pronouns, since it's Dean's POV and that's how he's used to thinking of Cas, but any confusion is entirely mine. Advice on how to tag properly would be appreciated! :D

Dean whimpers and doesn't move. "You wanna do it? Now?"

"Yes," Cas says. "Do you?"

"I—well, yeah. I mean, have you seen yourself? You make a really hot woman."

"Thank you," Cas purrs, and stretches his arms over his head, back arching in a way that draws Dean helpless steps towards him. "I like this body. It's a lot softer than my previous one, but there's strength to it, elegance. I want to experience its capabilities to the fullest." Cas wiggles his boxers down over his hips and throws them on the floor, and now he's all breasts, stomach, abundant thighs that frame a sleek delta of curls; and Dean takes a few more steps, fingers creeping to the hem of his T-shirt.

"But—does this not seem somehow wrong to you?" says Dean timidly.

Cas looks utterly mystified. "No, not at all. It does to you?"

"I don't know, it seems like—it took me so long to admit I liked dick, I feel like it's going backwards to have sex with a woman? Like I'm pretending I'm totally straight again."

"Dean," and Cas's voice is gentle, "that's not how sexuality works. You're as bi when you're having sex with a so-called female body as you are with a male one. And I'm not really a man _or_ a woman; I'm both, and neither. It's me that you love, isn't it? Not just my body?"

Dean nods. "Yeah. I was actually in love with you for years before I figured out I wanted you too. I'm kinda glad you took a male vessel—kept my hands to myself while I had the time to get to know you. I haven't really done that before."

"I've always wanted you—when I took the form of a man, when I was non-corporeal, and now. So please. Please come over here and make love to me." He lies back, parts his legs slightly, shoots Dean a saucy look that he must have learned from Meg. Which maybe should be a turn-off...but whatever faults Meg had (there were a lot), she was hot. Not as hot as lady-Cas, though.

Drawing a shaky breath, Dean takes off his shirt, his jeans and socks, and joins Cas on the bed in just his boxers. Cas turns on his side to face him, plump hip cocked, and Dean reaches out to touch the slope of him, the dip of his waist, slides his hand around to take a handful of ass. He whimpers again, and Cas smiles and kisses him.

His mouth is the same and not the same, and Dean quickly stops analyzing, runs his hands through Cas's hair, traces the smooth skin of his jaw, slides his hand down to cup a breast. It's warm and heavy in his grasp, the nipple firming under his palm, and Cas makes an _mmmm_ noise.

Dean kisses his neck, his collarbone, shifts to take a nipple in his mouth, brushing his fingers over the swell of a breast. "Mmmm," Cas says again, "more of that, please." So Dean pulls back, swipes his tongue over and around the nipple, tweaks it a little with his fingers. "Oh," murmurs Cas, "oh."

"Roll on your back," Dean says, pushing gently at his shoulder, and Cas allows it, baring his other breast to Dean's mouth; Dean pinches at the tip of it, licks and sucks until Cas's back bows. One of Dean's hands wanders down to Cas's hipbone, clutches it like a handle while his thumb massages the flesh around it. "Can I touch your, uh, pussy?" Dean asks, and Cas just reaches down and shoves the searching hand between his legs.

He's already a little wet, and Dean's thumb slips up the cleft to rub his clit softly—Cas jolts at the touch, throws his knee out to the side to give Dean better access. "That feels so good, Dean," he says, reverent.

"Yeah?" Dean says. "You want more? Or harder, or faster, whatever. Just tell me what feels good."

"Mmmm, what you're doing is perfect, keep doing that." So Dean keeps up a steady pressure on Cas's clit, rubbing in circles and dipping a finger into the gathering wetness below. Cas gasps and writhes as he works, spreads his legs wider; Dean pushes a finger into him slowly, in and out in time with the strokes to his clit. Suddenly, Cas seizes, moaning loud and low—"Stop," he says, and Dean takes his hand away, "I feel—fuck, Dean, it's _everywhere._ Is this—did you make me come?"

"Well, I was trying to, but that's kinda up to you, Cas. I don't have any idea what a chick orgasm is like."

"It was like—like an electric shock, but not painful. Quite the opposite."

"That's good! I can do it again in a minute, if you want. Or, uh, I could use my tongue. The ladies’ve told me I give good head." Dean grins up at him.

"I can do that again?" says Cas, eyes wide.

"Oh yeah. More than once, if I do it right. And I will," says Dean with a mischievous smirk. "Whatever you want."

"I want your tongue," Cas says decisively. "Lick me."

"With pleasure." Dean kisses down his stomach, nipping at the lush rolls of it, and pushes Cas's knees up. He teases his tongue up one inner thigh, sucks at the sensitive flesh while his hand parts Cas’s now-slick folds. Cas whines under his ministrations, jerks his hips up impatiently—and Dean relents, flicks his tongue over Cas's clit.

"Dean," says Cas in a strangled voice. "More, more."

It's been a while since Dean ate out a woman, but he's had a lot of practice, and he's actually kind of missed it. So he goes to town, uses every trick he knows to bring Cas over the edge again and again, until Cas's legs are shaking around Dean's head and his heels are digging into Dean's back almost painfully. Finally it's just too much stimulation, and Cas shoves him away, lies there panting with wonder in his eyes.

"Multiple orgasms are—they're awesome, Dean, thank you." Dean grins, props his chin on Cas's stomach.

"Do you want me to fuck you?" he asks. "We don't have to, you probably won’t like it as much as what I've been doing, but you did say you wanted the whole shebang."

"I do. It seems unfair that you only get to come once, though."

"Nah, I've been enjoying myself plenty, Cas, it's the way it goes." Dean's been pushing his hips into the mattress to get some friction on his aching cock; the breathy moans he's licked out of Cas are hot as hell, and he'd love to go for more. He swiftly doffs his boxers and rolls on a condom, kneels between Cas's legs—"Do you want me on top?"

"I want you right now," says Cas in a tone of command, and Dean sinks into him with a groan.

"You feel so good, Cas," he says, and kisses him on the mouth; Cas sucks his own taste off his tongue and rolls his hips, and Dean thrusts to meet him.

And then it's just the same, the details of bodies fading away, because all Dean wants is _Cas,_ and the rest doesn't matter. He's just having sex with the only person he's ever loved like this, surrounded by his love in return, and he keeps thinking in male pronouns just out of habit but he knows it's more complicated than that. This, though? this isn't complicated. This is just the two of them, the way it's supposed to be, and he comes with Cas's name pouring helplessly from his lips.

He pulls out to ditch the condom, flops back down and waits for his heart to stop pounding. It's Cas who speaks first: "I think Tiresias was on the right track, Dean. That was very, very good."

"It's us," Dean says. "Of course it was."

*******

They don't actually find a way to reverse the staff's spell. Instead, Sam suggests countering lore with lore: "There's an Albanian myth that jumping over the rainbow will change your sex. But I don't think it's a literal rainbow, guys—they refer to it as 'Lady Prende's belt,' and I think that's the same as Aphrodite's girdle. Which is a real thing, and I've already got leads on where to find it."

Cas nods. "Yes, let’s track it down. But…when we find it, can I keep it? I like this body, and I think I'll miss it. I want to keep my options open."

"Uh, sure," says Sam. "Does—Dean, are you okay with that?"

"Yeah," Dean puts his arm around Cas's waist, kisses his beardless cheek. "If it’s Cas, I'm okay with it."


End file.
